Summary

Name CHMP4B
Full Name Charged multivesicular body protein 4b
Synonyms Chromatin-modifying protein 4b, CHMP4b, SNF7 homolog associated with Alix 1, SNF7-2, hSnf7-2, Vacuolar protein sorting-associated protein 32-2, Vps32-2, hVps32-2 | C20orf178, SHAX1
Primary ID Q9H444
Links - -
Type protein
Relations 2
Function Probable core component of the endosomal sorting required for transport complex III (ESCRT-III) which is involved in multivesicular bodies (MVBs) formation and sorting of endosomal cargo proteins into MVBs. MVBs contain intraluminal vesicles (ILVs) that are generated by invagination and scission from the limiting membrane of the endosome and mostly are delivered to lysosomes enabling degradation of membrane proteins, such as stimulated growth factor receptors, lysosomal enzymes and lipids. The MVB pathway appears to require the sequential function of ESCRT-O, -I,-II and -III complexes. ESCRT-III proteins mostly dissociate from the invaginating membrane before the ILV is released (PubMed:12860994, PubMed:18209100). The ESCRT machinery also functions in topologically equivalent membrane fission events, such as the terminal stages of cytokinesis (PubMed:21310966). Together with SPAST, the ESCRT-III complex promotes nuclear envelope sealing and mitotic spindle disassembly during late anaphase (PubMed:26040712). Plays a role in the endosomal sorting pathway. ESCRT-III proteins are believed to mediate the necessary vesicle extrusion and/or membrane fission activities, possibly in conjunction with the AAA ATPase VPS4. When overexpressed, membrane-assembled circular arrays of CHMP4B filaments can promote or stabilize negative curvature and outward budding. CHMP4A/B/C are required for the exosomal release of SDCBP, CD63 and syndecan (PubMed:22660413).

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Relations

Regulator Mechanism target score
+ form complex img/form-complex.png binding ESCRT-III 0.718
Publications: 1 Organism: In Vitro
+ up-regulates activity img/direct-activation.png binding CHMP4B 0.434
Publications: 1 Organism: Homo Sapiens